Slippery Surfaces Save Energy

In virtually all machinery, from your vacuum cleaner to factory assembly lines, oil or grease lubricates the moving parts to reduce friction. Friction wears out parts quickly and raises the energy expended in moving them. Anything that can cut such resistance should lengthen the life of machines and save energy. U.S. government estimates indicate, for example, that even a modest improvement in the efficiency of the common hydraulic pump could save American industry hundreds of millions of dollars in annual energy costs.

Aiming at such a result, researchers at the U.S. Department of Energy’s Ames Laboratory in Iowa have developed a coating for machine parts that makes their exteriors considerably slicker and more resistant to wear. Ten years ago Ames materials scientists Alan Russell and Bruce Cook discovered a ceramiclike alloy of boron, aluminum and magnesium—nicknamed BAM—that exhibits exceptional hardness and extremely low surface friction.

When BAM is lubricated with standard fluids such as water-based oil emulsions, it is more slippery than DuPont’s Teflon coating (of nonstick cookware fame), Russell says. In tests, the substance significantly outperforms most industrial coatings.

Engineers at companies including Eaton and Greenleaf are readying BAM for use on hydraulic pump parts, machine-tool cutting inserts and the nozzles of abrasive water-jet cutting tools. Although the first of these products is still several months away from commercialization, the patented material is currently available from a licensee, NewTech Ceramics in Des Moines